API (Phase Interpolator) is a circuit that generates, during an actual operation of a semiconductor device such as an LSI (Large Scale Integrated Circuit) and the like (during system operation in a case in which the semiconductor device is integrated in to a computer device), a signal of a desired phase in an IO macro (Input Output Macro Cell) being an input/output circuit cell of an external interface of the semiconductor device. The operation of the phase interpolator is checked by performing a function test included in an LSI test in the LSI manufacturing process.
For example, to a mixer constituting the phase interpolator, static signals, specifically, two potentials that are different from each other for example, a low level signal and a high level signal are applied. In this state, by a control signal (digital signal), a control switch of the current source is switched in a DAC (Digital Analog Converter) that constitutes apart of the mixer. Accordingly, in the output of the phase interpolator, the weighting of the two input potentials is changed, to check the change in the output level. By judging the output level of, the static operation of the phase interpolator in the function test is checked.
Meanwhile, in a semiconductor integrated circuit and a testing evaluation method thereof, measurement of the voltage value of a direct current voltage by smoothing a voltage waveform output from a chain circuit composed of logic gates into the direct current voltage by a phase difference/voltage conversion circuit has been known.
In addition, in an input check circuit, an input check method and in a burn-in substrate, identification of any input trouble by connecting a plurality of input terminals respectively to the gate terminal of a P channel transistor upon the check, a plurality of input signals whose phases are shifted from each other are respectively input to the input terminal, to identify whether there is any input trouble has been known.